Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752719AbbDCVIl (ORCPT ); Fri, 3 Apr 2015 17:08:41 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:33108 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751186AbbDCVIj (ORCPT ); Fri, 3 Apr 2015 17:08:39 -0400 Date: Fri, 3 Apr 2015 14:08:37 -0700 From: Omar Sandoval To: dsterba@suse.cz, "Eric W. Biederman" , Chris Mason , Josef Bacik , Timo Kokkonen , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] Btrfs: prevent deletion of mounted subvolumes Message-ID: <20150403210837.GA13535@mew.dhcp4.washington.edu> References: <64e28e67cbab0a2cd97411b848911414a743d83f.1427705646.git.osandov@osandov.com> <20150330123034.GB32051@suse.cz> <20150330184135.GA27227@mew.dhcp4.washington.edu> <87k2xwv6y8.fsf@x220.int.ebiederm.org> <20150401070328.GA27048@mew> <20150401112242.GG6821@suse.cz> <20150402034954.GA25368@mew.Belkin> <20150402150225.GJ6821@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150402150225.GJ6821@twin.jikos.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1429 Lines: 33 On Thu, Apr 02, 2015 at 05:02:25PM +0200, David Sterba wrote: > On Wed, Apr 01, 2015 at 08:49:54PM -0700, Omar Sandoval wrote: > > Hm, yeah, that's unfortunate, thanks for pointing that out. It looks > > like we can get the subvolume ID reliably: > > > > ---- > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > > index 05fef19..a74ddb3 100644 > > --- a/fs/btrfs/super.c > > +++ b/fs/btrfs/super.c > > @@ -1024,6 +1024,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) > > struct btrfs_root *root = info->tree_root; > > char *compress_type; > > > > + seq_printf(seq, ",subvolid=%llu", > > + BTRFS_I(d_inode(dentry))->root->root_key.objectid); > > yes, subvolid is reliable, but not very friendly from users' POV. I'd > like to see subvol=/path there. Possibly we can have both. So are you saying that we should try to fix the bug in userspace by first getting subvol/subvolid in /proc/mounts, or do you want to keep that a separate issue? Just asking because you didn't comment on the kernel-side fix. Here's a concrete implementation of what I'm talking about: https://github.com/osandov/linux/tree/btrfs-delete-mounted-subvol. -- Omar -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/